Hearing Loss

CONDUCTIVE HEARING LOSS etiologies

(mechanical dysfunction in transmitting sound to inner ear; issue w/ external or middle ear) External auditory canal occlusion Tympanic membrane perforation Otitis media Otosclerosis and ossicular ankylosis Otitis externa Tumor Congenital aural atresia

Noise-induced hearing loss features

- Classically worse at 4 kHz (audiogram) - Mostly symmetric (noise exposed to both ears) - Don't attribute unilateral hearing losses to chronic noise exposure!!!

1. Tuning fork test

- Weber - to determine if there is pathology whether conductive pathology (hear in dysfunctional ear) or sensorineural pathology (hear in good ear) - Rinne - resolves ambiguity from Weber's test; air conduction >> bone conduction in the good ear Ex: Weber lateralizes to the R ear; Rinne air conduction < bone conduction in R ear --> sensorineural pathology (confirm)

Noise-induced hearing loss

- acoustic trauma that is acute or chronic - typically worse at 4 kHz - often assoc with occupational hearing loss - usually symmetric - don't attribute unilateral hearing loss to chronic noise exposure Rx: No Rx; amplification is key

Presbycusis

- assoc w/ aging - some hereditary component (all elderly do not lose hearing) Rx: hearing aids

Red Flags

- chronic otits externa - painful otitis external among pt w/ diabetes - unilateral COME - pulsatile tinnitis - unilateral / asymmetric tinnitis - sudden sensorineural hearing loss - unilateral chronic ear pain

Risk factors for newborn hearing loss

- family hx - maternal infection during pregnancy - low birth weight - hyperbilirubinemia - ototoxic meds - mech ventilation > 5 days - agar scores of < 5 at 1 min or < 7 at 5 min (???)

Presentation of Vestibular Schwannoma

- may present late - rarely facial or cochlear nerve - asymmetric SNHL - unilateral tinnitis - unexplained dizziness - asymmetric speech discrimination - sudden SNHL

What do you do when presented w/ unilateral otalgia (ear pain)?

- normal ear exam - normal audiogram - think of referred pain from pharynx or larynx eg. neoplasm - unilateral ear pain -- keep looking!

f. Congenital Aural Atresia

- occurs w or w/o microtia (small auricle) - INNER EAR is NORMAL but branchial cleft anomalies (ear canal, ossicles, etc) - varying degrees of EAC stenosis / atresia Rx: sometimes mild middle ear anomalies; sometimes surgical correction

Chronic otitis media with effusion (COME)

- often occurs after acute otitis media (pus in middle ear -> bacterial die -> leaves serous effusion) and leads to eustachian tube dysfunction (plugs it up) Rx: resolves over time; Abx may help decrease time to recovery, steroids, surgery

Techniques for auditory function assessment

- tuning fork testing - pure tone audiometry - speech audiometry - acoustic reflexes - auditory brainstem response audiometry (ABR)

Etiology - neoplasm

- usually slowly evolving facial paralysis (*** imp to distinguish from others) - funny combo of cranial neuropathies - failure of Bell's recovery most common = parotid tumors (malignant) also - schwannoma, paraganglioma, leukemia, metastasis

Etiology - Infections

-often herpes simplex neuritis - labyrinthic portion of facial n is esp vulnerable (tight fit space of travel) so if facial n swells (neuritis) then this can lead to compressive neuropathy - majority idiopathic - infection - HSV, herpes zoster (pretty uncommon; treat aggressively and use anti-viral; more pain; poorer prognosis; increased hearing and vest loss) - infection from otitis media (acute from fluid in ear; chronic from cholesteatoma - good prognosis from resolution or surgery (latter)) - lyme disease infection (neurologic complications, cardiac, RA; rx = 3 to 4 wks Abx) - otitis externa from osteomyelitis of skull base --> compress facial n (esp among elderly patients w/ draining ear)

Congenital causes of sensorineural hearing loss

1. Acquired - intrauterine insult - maternal rubella, CMV, herpes, syphilis, toxo, hyperbilirubinemia (esp among premature infants), teratogenic drugs (quinine, thalidomide) 2. Hereditary - usually as isolated disability; 90% AR; can be syndromic or non-syndromic

Key Points

1. Don't assume all facial paralysis is Bell's 2. Atypical histories - think of neoplasm slow onset of paralysis recurrent unilateral paralysis lack of early recovery 3. Bell's patients do not have a uniformly good spontaneous recovery rate (15% w/ poor outcome) 4. Treat - steroids (probably), antivirals (possible), surgical decompression (possible)

Rx of Meniere's Disease

1. Na restriction, diuretics (to rid Na in body) 2. ENdolymphatic sac decompression 3. vestibular ablation (to stop the vertigo!)

Treatment of Tinnitis

1. Treat underlying pathology 2. Masking (esp if worse in quiet env) - raise level of ambient background w/ hearing, etc 3. Rehabilitate hearing loss - hearing aid, correct conductive hearing loss, cochlear implants Cannot "cure" it

Tumors that cause sensorineural hearing loss

1. Vestibular schwanomma (acoustic neuroma) 2. Neurofibromatosis Type II (subtype of vestibular schwanomma) 3. Meningioma - presents like VS 4. Glomus tumors - erode into cochlea or auditory nerve 5. Epidermoids

2 major classifications of hearing loss

1. conductive - not conducting sound to inner ear; pathology in external or middle ear 2. sensorineural - sound not being transduced or interpreted; problem in cochlea (sensory) or neural (auditory n, brainstem, brain); or both

e. Tumors causing conductive hearing loss

1. external auditory canal skin tumors - squamous or basal cell (not common) 2. glomus tumors (neural endocrine tumors) eg. glomus jugulare (grow on jugular foramen and affect CNs) or glomus tympanicum (arise on cochlear surface - benign, grows slowly)

Purpose of auditory function assessment

1. functional assessment - are you at risk of falling? 2. site of lesion - what is going on? where is the pathology?

Types of tinnitis

1. objective - detectable by examiner - pulsatile tinnitis (blood flow) - venous hum, bruit, intracranial HTN 2. subjective - not detectable (most common); commonly associated w/ sensorineural hearing loss

General Rx for Chronic Otitis Media

Abx (if related to an infection) Surgery - mastoidectomy - open up hollow mastoid - helps w/ surgical exposure of an area - intact canal wall type (remove back wall of ear canal) - cana wall down type (remove posterior ear canal wall to open up mastoid cavity) - usually conducted w/ a meatoplasty **do we need to know this?

c. Otitis media - general description, types

Acute or chronic Various pathologies - serous (middle ear effusion, not pus) - secretory (chronic otitis media w/ effusion) - suppurative (w/ frank pus) - mucoid (w/ mucus) - adhesive (atelectatic - ear drum sucked in/retracted)

Exs of hereditary causes of congenital sensorineural hearing loss

Alport's, Waardenburg's do we need to know these?? check 1st aid

Vestibular Schwannoma - type of tumor - presentation

Benign tumor of vestibular nerve Very common and sporadic (just arises!) Slow loss of vestibular function Can present w/ hearing loss

What is the hallmark feature of NF Type II? Rx?

Bilateral VS Rx - cannot use cochlear implants b/c may need to remove cochlea

Cholesteatoma

COME can occur w/or w/o cholesteatoma - cyst lined w/ keratinizing squamous epithelium - mostly acquired but can also be congenital - presents w/ some hearing loss; crust on top of tympanic membrane (squamous debris) b/c pars fasita(sp?) caves in -> debris builds up -> pockets get deeper -> more debris -> starts to erode bone around incus, ear canal, etc - can be v. serious and cause abscesses or facial n paralysis (over decades)

c1. acute suppurative otitis media - clinical presentation - usual pathogens - rx

Conductive Hearing Loss (tympanic membrane cannot vibrate w/ pus around) VERY common among children (esp before 3 y/o) - pus, pain, fever w/ red tympanic membrane Pathogens - S pneumo; H infl; B catarrhalis Rx - Abx but some resolve spontaneously (controversy)

What kind of hearing loss is this? -abnormal air conduction -normal bone conduction

Conductive hearing loss

Chronic suppurative OM, inactive

Conductive hearing loss perforated space drains pus which can lead to an infection (esp pseudo, staph) preseenting foul-smelling otorrhea Rx: surgery to fix the perforation and treat chronic infection if necessary

Chronic suppurative OM, active

Conductive hearing loss perforated space drains pus which can lead to an infection (esp pseudo, staph, anaerobes) preseenting foul-smelling otorrhea Rx: surgery to fix the perforation and topical Abx (b/c active infection)

d. Otosclerosis

Conductive loss in normal appearing ear! Disease of otic capsule bone (where inner ear originates) - otic one remodels during development and causes stapes bone to become stuck (cannot vibrate) - multifactorial genetics - typically starts in adulthood (can be precipitated by pregnancy) Rx: hearing loss is flexible; can remove stapes and place prosthetic

Meniere's Disease

Inner ear disorder that causes triade: - fluctuating hearing loss (gets worse over years) - tinnitus - episodic vertigo (lasts hrs) May have endolymphatic HTN in 1 ear

Ototoxicity

Many common drugs are ototoxic esp aminoglycosides (tobramycin, gentamycin) and platinum drugs Affect vestibular and hearing function

2. Audiogram

Measures level of sound loudness (dB) that can be detected at various frequencies. a. Air conduction - pure tone presented through microphones through ext ear to middle to inner (measures conduction and sensorineural) b. Bone conduction - directly place tone to inner ear (measures sensorineural) c. Conduct similar tests w/ hearing speech at different loudness - speech reception threshold v. speech discrimination tests (% of words that can be heard)

SENSORINEURAL HEARING LOSS - etiologies

Noise induced Presbycusis Sudden Sensorineural Hearing Loss (SSHL) Ototoxicity Meniere's Disease Infection Autoimmune Congenital - acquired; hereditary Tumors

What kind of hearing loss is this?

Noise induced hearing loss Sensorineural hearing loss ** classically worse at 4 kHz

TINNITIS

Perception of sound when you're not being exposed to sound eg. ringing in the ear Tends to correlate w/ hearing loss (either conductive or sensorineural) although it also occurs w/ normal hearing (eg from acute noise exposure - resolves)

Central Hearing Loss - bilateral vs. unilateral

Rarely unilateral cortical problems that lead to hearing loss b/c hearing is bilateral after the cochlear nucleus (in ponto-medullary junction of brainstem) May be due to MS, brain tumors, ischemic insults

Treatment of sensorineural hearing loss

Rx underlying pathology Avoid further insults Hearing aids Cochlear implants Auditory brainstem implant

SSNHL Management

Rx: steroids (increases recovery) - Treat as emergency - do not assume otitis media w/ effusion in 1 ear - All receive MRI to ensure that it's not an acoustic neuroma

What kind of hearing loss is this? -abnormal air and bone conduction scores - sometimes reduced speech discrimination

Sensorineural hearing loss

What type of information is provided by an audiogram?

Site of lesion (conduction or sensorineural) and severity of damage

Sudden Sensorineural Hearing Loss (SSNHL)

Sudden lose of hearing in one ear, usually due to viral neuritis but 1% will have acoustic neuroma

Neurofibromatosis Type II

Type of VS among those who inherit an abnormal merlin gene (usually synthesizes a tumor suppressor protein). Characterized by multiple schwannomas and meningiomas Hallmark is bilateral VS

a External auditory canal occlusion - causes - rx

common cause of conductive hearing loss - impacted cerumen v. common; foreign body; swimmer's ear (cellulitis of ear canal skin -> can lead to infection) Treatment: debridement (microscope + suction); topical Abx; steroids help reduce edema

What is the red flag w/ unilateral COME?

ensure that there is not a skull base or nasopharyngeal neoplasm

b. Tympanic membrane perforation - common causes - rx

hearing loss is variable, depending on size of perforation and location of perforation - common causes - infection, trauma (water, punch), tympanostomy tubes - rx: often heal itself but depends on extent of perforation

Facial Paralysis

not uncommon

If an elderly pt has a draining ear, ear pain and facial n paralysis

osteomyelitis of skull base - refer!

Bell's Palsy

rapid onset of unilateral facial paralysis even within a day; majority recover spontaneously

Painful otitis external in a diabetic and/or elderly patient - what could this represent?

skull base osteomyelitis (malignant OE) -- ear pain, ext otitis media

Etiology - trauma

temporal bone fractures (#2 most common etiology - MVA)

Unilateral tinnitis - what do you do?

think tumor --> get MRI to rule out / or in acoustic neuroma

Atelectatic chronic OM

tympanic membrane retracted and stuck down on the incus and stapes -- eventually the incus disappears

c2. Chronic otitis media

wide range of disease processes including chronic middle ear effusions, persisting tympanic membrane perforations, cholesteatoma, atelectatic disease